ABSTRACT
Objective@#To explore the method of extracting chaperone antigen peptide complexes from gastric cancer stem cells and its immune function.@*Methods@#Gastric cancer stem cells and gastric cancer cells were screened by low temperature ultrasonic lysis. After salting out and dialysis, the lysate supernatant was processed with SDS-PAGE to analyze the expression of chaperone antigen peptide complexes, and then was separated and purified with CNBr-activated SepharoseTM 4B. Reverse high pressure liquid chromatography (HPLC), SDS-PAGE and Western blotting were used to analyze the purity and nature of the acquired albumen. Lymphocyte proliferation assay and lymphocytotoxicity assay were used to ditermine the immunological activity of the chaperone-antigen peptide complexes.@*Results@#The chaperone antigen peptide complexes of gastric cancer stem cells were prepared and identified successfully, of which the main components were the antigen peptides of HSP60, HSP70, HSP90 and HSP110. 0.75 μg and 1.00 μg HSP70-antigen peptide and 1.00 μg HSP90-antigen peptide activated lymphocytes significantly. Their A490 values were 0.26±0.03, 0.45±0.05 and 0.32±0.04, respectively, while the corresponding doses of HSP60-antigen peptide and HSP110-antigen peptide did not activate lymphocytes. The killing rates of 1.00 μg HSP70-antigen peptide and 1.00 μg HSP70 were (45.0±2.0)% and (16.0±2.0)%, respectively, showing a significant difference (P=0.012). Similarly, the killing rates of 1.00 μg HSP90-antigen peptide and 1.00 μg HSP90 were (36.0±5.0)% and (13.0±4.0)%, respectively, also showing a significant difference (P=0.048).@*Conclusions@#The amount of chaperone antigen peptide complexes in gastric cancer cells is extremely low, but it is obviously increased in gastric cancer stem cells. After purification, the chaperone antigen peptide complexes with high purity can be prepared. The extracted chaperone antigen peptide complexes have stronger immunogenicity, and can be used to make tumor vaccine in vitro, which may have a good application value in the targeted therapy of gastric cancer.
ABSTRACT
[Abstract ] Objective Difficulties with the preparation of gastric cancer stem cells (CSCs) have been a main obstacle to the studies of gastric cancer .This article addresses the technology of the serum-free medium suspension cultivation of the MKN-45 gastric cancer cell line and screening of stem cells from the cell line based on the biomarkers of gastric CSCs . Methods MKN-45 cells were cultured in serum-free medium for 8 weeks and those in the logarithmic phase cultivated with hoechst 33342 followed by detection of the side cells by flow cytometry .When the side population cells reached 25%, all the cell microspheres were collected , hatched with CD133 and CD44, and subjected to fluorescence-activated cell sorting.The CDl33 +and CD44 +cells were selected as gastric CSCs . Results About 40%of the MKN-45 gastric CSCs were alive , prolif-erated, and formed floating cell balls .Side population cells constitu-ted 3.4% of the MKN-45 cells and 26.9% of the cell balls.The CDl33 +and CD44 +cells made up 11.2% of the MKN-45 cells and 90.3%of the cell balls. Conclusion Cell balls rich in CSCs can be successfully obtained by serum-free medium suspension culti-vation and CSCs can be screened out with hoechst 33342 and surface markers , which may serve as an experimental ground for the stud-ies of gastric CSCs .